This invention relates to a method and apparatus for draw forming glass fibers wherein a flow of air established adjacent a melt furnace is first directed across the orifice plate thereof to provide additional cooling capacity during the initial start-up period, and is thereafter directed downwardly parallel to the fiber or filament flow to provide a heat shielding air curtain to protect the operator.
In the manufacture of glass fibers it is generally desirable to minimize the diameter of the fibers while at the same time maximizing or enhancing productivity. To this end a plurality of flow holes are typically formed in the bottom orifice plate of a melt furnace at a high density such that molten glass cones are formed at the orifice outlets closely adjacent one another, and are simultaneously cooled and drawn down into thin filaments. As the hole density increases, however, there is a tendency for the cones and filaments to contact each other and flood, particularly during the initial start-up period. If during such period, however, air is blown across the orifice plate surface in a direction parallel or slightly inclined thereto to cool the molten glass cones and increase their viscosity, the convergence of the filaments can be prevented during their formative period. Such a technique is disclosed in Japanese Laid-open Patent Application No. 7218/1976, for example.
It is also known to form a protective air partition or curtain to separate an operator's working area from a hot glass fiber draw forming area, as evidenced by Japanese Patent Application Publication (OPI) No. 30051/1970 (U.S. Ser. No. 657,622 (Aug. 1, 1967)).